The invention relates to an arrangement of a child seat on a vehicle seat and a method of fastening a child seat on a vehicle seat.
Up to now, child seats in vehicles have usually been fastened by means of the vehicle-side belt system or by means of additional belts mounted in the vehicle. In the future, there will be the so-called ISOFIX Standard which is established or will be established in various standards. The ISOFIX Standard requires a basically rigid connection to adapters on the vehicle seat by means of locking elements on the child seat. As a result of this direct connection, the child seat is decelerated with the vehicle without any time shift. The connection of a child seat to a vehicle seat according to the ISOFIX Standard is described, for example, in German Patent Document DE 299 03 414 U1.
However, it is a disadvantage of a connection according to the ISOFIX Standard that, in the event of a crash, the child will still experience a certain forward displacement in the driving direction as a result of the child seat""s own belt system, while the child seat itself remains rigidly connected with the vehicle seat. This reduces the child""s wedging in the vehicle seat. Particularly in the event of a rebound, there is the danger, in the case of a child seat with a lap belt and a catch tray, that the child may be xe2x80x9cpulled outxe2x80x9d of the child seat.
This danger is avoided or reduced by a child seat of the invention in that, in the event of a crash-caused deceleration of the vehicle, a limited displacement of at least the backrest of the child seat in the driving direction takes place in order to compensate the child""s displacement within the child-seat-side belt system. As a result, the child is held in an unchanged tight contact with the child-seat-side belt system and the child seat. This results in a higher safety for the child, in addition to the advantages achieved by the ISOFIX connection.
Although from European Patent Document EP 0 927 659 A2, an arrangement of a child seat on a vehicle seat by way of an ISOFIX system is known. In the case of the known arrangement, a deformation element is provided between the vehicle seat and the child seat, by means of which deformation element, peak loads in the detent device and/or fastening device of the ISOFIX system are to be reduced. As a result of the relative movement of the child seat with respect to the vehicle seat caused during a deforming of the deformation element, force peaks are reduced as they occur in the event of the impact of unsecured cargo on the rear seats of the backrest of the vehicle seat.
In contrast, in the case of the present invention, devices are provided at the child seat which permit a relative movement (of the backrest) of the child seat with respect to the child-seat-side fastening device, in which case, however, the child-seat-side belt system remains rigidly connected with the fastening device in order to restrain the child as best as possible. In contrast, as a result of the deformation element according to European Patent Document EP 0 927 659 A2, the child-seat-side belt system participates in the same manner in the limited forward displacement caused by the deforming of the deformation element as the entire child seat, with the initially mentioned disadvantages mentioned concerning the prior art.
The invention is preferably implemented by a displacement of the entire child seat with respect to the vehicle seat. However, to achieve the advantages of the invention, it is sufficient to permit a displacement of the backrest alone.
The vehicle-side belt system is formed, for example, by a lap belt with a catch tray. The invention has a particularly advantageous effect with respect to such a system because the increased wedging of the child according to the invention limits the forward displacement and reliably prevents a xe2x80x9cpulling-outxe2x80x9d of the child during the rebound. By means of the invention, it is also possible to bring a child seat with a catch tray into a sleeping or comfort position in which the backrest of the child seat has a larger inclination angle with respect to the seat surface so that the distance between the backrest and the catch tray is enlarged. The displacement (of the backrest) of the child seat permitted according to the invention in the event of a crash ensures a still sufficient wedging of the child in the child seat also in the sleeping or comfort position.
In principle, the invention can also be used in the case of child seats with a child-seat-side multipoint belt system without a catch tray with a 5-point belt system. It also has an advantageous effect in the case of child seats whose multipoint belt system is displaced with the child seat in the event of a crash, because energy can additionally be reduced by the devices for displacing the backrest of the child seat, for example, an expandable slot or a shear bolt.